<html>
  <script>
    async function toggleFullscreen() {
      if (!document.fullscreenElement) {
        await document.documentElement.requestFullscreen();
        await screen.orientation.lock("landscape-primary");
      } else {
        document.exitFullscreen();
      }
    }
  </script>
  <body style="height:5000px" onclick="toggleFullscreen();">
    <p>A page that will rotate on touch.</p>
  </body>
</html>
